This invention relates to a 3-D TV image viewing system, and mainly to system for viewing 3-D TV images of a high quality by eliminating a flicker.
Flicker has been caused by the light shutters used in conventional 3-D TV systems, in which the shutter period of the light shutters is synchronized with the display period of the TV images to obtain a fused stereoscopic image consisting of both the left image and the right image corresponding to the human eyes. In the prior art system, the left and right images are picked up alternatingly by each field. In the conventional TV systems, the switching periods (T.sub.v) are defined as follows: about 1/60 of a second in the NTSC system adopted in both Japan and the U.S.A., and about 1/50 of a second in the PAL system adopted in both G.B. and W.G. and in the SECAM system adopted in France and the U.S.S.R. The time period for fusing the left and the right image fields into a single stereoscopic frame is twice the switching period (2T.sub.v). The value for fusing is above the threshold value (.apprxeq.1/45 of a second) for the human eye to be sensitive to flicker. In practice, during the 3-D TV viewing of the video signals from an image recording apparatus, for example-a VTR, the flicker effect causes human eyes to feel a slight fatigue.